The invention relates to traction apparatus acting on a cable through two self-clamping clamps with reverse alternating movements for warping in and out of the cable.
Apparatus of this kind, such as the one described in French Pat. No. 914 400 of Sept. 5, 1945, are generally anchored to a fixed point by means of a hook. This anchorage is efficient but space-consuming and it has appeared that a pin mounting offers practically the same results for a smaller space occupied, a reduced weight and a lower price. However, the securing pin must find in the case of the apparatus adequate contact surfaces; on the other hand, in the anchorage zone, the metal section must be compatible with the stresses undergone by the case of the apparatus, which stresses are increased by a large safety coefficient. This explains why most traction apparatus with an anchorage pin are cast and not made from pressed steel sheet.
In fact, a pressed steel sheet construction requires the creation of a sort of ribbed casing whose different components must be firmly assembled together. Now, the usual methods of assembly, welding or riveting, present in this case different drawbacks, in particular the multiplication of the corrosion points in zones inaccessible for painting or for another mode of protection.
The present invention provides then a traction apparatus with pin anchorage which is designed to avoid the above-mentioned disadvantages and which offers a great strength in operation in particular under a high load, while allowing easy construction thereof.